Liquid coating composition comprising a vinyl chloride dispersion resin, a vinyl chloride copolymer solution resin and acrylic resin in an organic vehicle and metal coated therewith



United States Patent 3,418,274 LIQUID COATING COMPOSITION COMPRISING AVINYL CHLORIDE DISPERSION RESIN, A VINYL CHLORIDE COPOLYMER SOLUTIONRESIN AND ACRYLIC RESIN IN AN ORGANIC VEHICLE AND METAL COATED THEREWITHRichard E. Caplan, Waukegan, Robert H. Rosenthal,

Highland Park, and Richard W. Clope, Zion, Ill., assignors, by mesneassignments, to The Dexter Corporation, a corporation of Connecticut NoDrawing. Continuation-impart of application Ser. No. 368,321, May 18,1964. This application Dec. 15, 1965, Ser. No. 514,108

13 Claims. (Cl. 260-41) ABSTRACT OF THE DISCLOSURE Disclosed is a liquidcoating composition, suitable for use as a baked-on metal coating, whichcomprises -70% by weight of non-volatiles containing 10-34 parts percentvinyl chloride dispersion resin, 9-34 parts of vinyl chloride copolymersolution resin, and about 2-40 parts of acrylic resin in an organicliquid vehicle.

The present application is a continuation-in-part of our copendingapplication Ser. No. 368,321, filed May 18, 1964 now abandoned, which isa continuation of our copending application Ser. No. 120,154 filed June28, 1961, now abandoned, which was a division of our copendingapplication Ser. No. 70,909, filed Nov. 22, 1960 now abandoned.

This invention relates to coating compositions and metal surfaces coatedtherewith.

These coating compositions may be easily applied as a liquid and bakedon the surfaces of a wide variety of metals without requiring the priorapplication of a primer coating composition. The resulting baked-oncoating adheres tenaciously to the underlying surface and has goodtoughness properties.

Further, by controlling the preparation of and constituents in thecoating composition (substantially homogeneous), one may prepare acomposition that produces a coating with (a) either a high gloss finishor low gloss finish with low or high angular sheen, (b) good colorretention, (c) good weatherability, (d) good chemical resistance, and(e) good flexibility. The outstanding flexible and adhesive qualities ofthe coating permit the coated metal to be fabricated (for example, bentin a brake or by roll-formers) or further treated or shaped for its enduse without chipping, peeling or fracturing from the metal surface toexpose said surface.

Still further, the liquid coating composition may be stored, prior toits application to metal surfaces, for periods of about six monthswithout any material change in its viscosity, although some increasegradually occurs during this period. However, if the composition is tobe stored for longer periods of time, the viscosity may be adjusted byadding solvents and diluents.

Our coating compositions are particularly well-suited for coatingaluminum (includes aluminum alloys), as well as copper, ferrous metalssuch as steel, and zinc die castings. The coating (e.g., strip coating)of aluminum is of particular importance because this metal isparticularly well suited for post-forming operations. The metal need notbe first coated with an organic primer, however, the metal should befirst treated in the customary manner with a conversion coating such asAlodine 1200 S or Bonderite 721. Both Alodine 1200 S and Bonderite 721are used to form amorphous chromate coating. Their formulations arecomposed of hexavalent chromium ions,

fluoride ions and ferricyanide ions similar to those described in US.Patent 2,796,370.

The liquid coating compositions embraced by our invention may be appliedto metal surfaces by the usual roll-coating machines, or they may beapplied by brushing, spraying or dipping operations. After the liquidcoating composition is applied to the metal surfaces, the coated metalshould be baked for approximately 1-4 minutes at about 350-450 F. Wehave found that excellent results are obtained when the coated metal isbaked for 1 /2 minutes at 400 F.

It is indeed remarkable that a substantially homogeneous liquid coatingcould be prepared having a combination of such outstandingcharacteristics.

The liquid coating compositions (as applied to the surfaces to becoated) embraced by this invention may contain the following components:

(a) An organosal dispersion resin component;

(b) A solvent and/or diluent (includes combinations thereof);

(0) A plasticizer (includes combinations thereof);

(d) A stabilizer (includes combinations thereof);

(e) A vinyl chloride copolymer solution resin component;

(f) A vinyl chloride-vinylidene chloride solution resin component;

(g) An acrylic resin component comprising a non-airdryin-g acryliccasting type resin syrup and/or an air-dry or bake (thermoplastic orthermosettin-g) solution type acrylic resin; and

(h) A pigment (includes a combination thereof).

In some instances, an ingredient or component may provide multiplefunctions. An ingredient, for example, may serve as both a plasticizeras well as stabilizer.

If desired, the pigment may be omitted. The plasticizer and/or vinylchloride-vinylidene chloride components, for example, may likewise beomitted; however, superior results may be obtained when they are presentin the coating composition.

Components (e)-(g), above, are considered as being organosol resinmodifiers.

The term organosol herein refers to compositions that contain vinylchloride polymer and volatile dispersing liquid and/or diluent.

The plasticizer, modifying resins, diluent and solvent may be separatelyincorporated into the liquid coating composition or added thereto aspart of the organosol component.

The organosol dispersion component is a dispersion of a vinyl chlorideresin, such as polyvinyl chloride and/or polyvinyl chloride-diethylmaleate copolymer resin. It contains, in addition to the resin, adiluent and/or dispersant. The vinyl resin should contain at least aboutby weight of polymerized vinyl chloride, preferably more. Particularlygood results are obtained with a vinyl chloride resin having an averagemolecular weight of at least about 20,000.

A stabilizing agent that inhibits thermal and ultraviolet decompositionis used in conjunction with the vinyl chloride resin. In addition, ifdesired, a suitable plasticizer may be present in or added to theorganosol resin component.

Commercially available vinyl chloride dispersion grade resins such asthe following may be used in the organosol component: Bakelite OYNV is awhite powdered solid containing about 98-99% by weight polyvinylchloride, and has a specific gravity of about 1.40 and a specificviscosity from about 0.240 to 0.32 as measured by 0.2 gm. resin per 100ml. of nitrobenzene at 20 C.; Opalon 410" is a dispersion gradepolyvinyl chloride of a stir-in type having the following properties:consistencypowder, color-white, specific gravityabout 1.40, specificviscosity (solution of 0.40 gm. of polymer in 100 ml. of cyclohexanoneat 25 C.)-0.53-0.55, particle size 1-2 microns, dry bulk densityabout0.25-0.35 gm./cc., loss in Weight on heatingabout 0.5% max., ash-about0.5% max.; Geon 121 is a stir-in type high molecular weight polyvinylchloride resin in the form of a fine white powder, has a specificgravity of about 1.4, a bulk density of about 20-25 lbs./ft. and has aspecific viscosity of about 0.57-0.63; Exon 654 is a high molecularweight dispersion type polyvinyl chloride (white powder) product havinga specific gravity of about 1.4 and average relative viscosity of about2.65; and Pliovic A is a vinyl chloride dispersion resin or copolymercontaining about 95% by weight vinyl chloride and some other modifyingmonomer such as diethyl maleate units (similar products are shown inBair Patent 2,492,086), has an average particle size of 1-2 microns, anintrinsic viscosity of 0.85, a specific gravity of 1.39, and a bulkdensity (packed) of 21.5 lbs./ft.

The organosol component contains a diluent and/or dispersant such asexemplified by aliphatic hydrocarbons such as V. M. and P. naphtha,aromatic hydrocarbons (e.g., Penola 150, toluol and xylol), esters(e.g., butyl acetate, amyl acetate), ketones (e.g., diacetone alcohol,methyl ethyl ketone, methyl isobutyl ketone, isophorone, and diisobutylketone), glycol ethers (e.g., diethylene glycol monobutyl ether anddiethylene glycol monoethyl ether), and nitropzraffins (2-nitropropane).(Penola 150 has 94% by volume aromatics (ASTMD875), a mixed anilinepoint C.) of 20, a flash point (Tag closed cup, F.) of 150, aKauri-Butanol value of 89.1 and a specific gravity (60/ 60 F.) of0.8925.)

The aliphatic hydrocarbons and aromatic hydrocarbons serve as diluents.The ketones, esters and nitroparaflins serve as dispersants. The glycolethers are both diluents and dispersants.

The organosol component also includes or is used in conjunction with aplasticizer. The plasticizer, for example, may be a phthalate ester, anester of a straight chain dibasic acid, a phosphate ester, or apolyester. More specifically, the plasticizer may be a member of thegroup comprising dioctyl phthalate, diisooctyl phthalate, didecylphthalate, n-octyl n-decyl phthalate, diisodecyl phthlate, dioctyladipate, diisoadipate, dibutyl adipate, diisodecyl adipate, n-octyln-decyl adipate, tricresyl phosphate, cresyl phenyl phosphate, trioctylphosphate, dibutyl sebacate, dioctyl sebacate, and an epoxidized oilsuch as Paraplex G-62. Paraplex G-62 has a molecular weight (average) ofabout 1,000, a color (Gardner Varnish Scale) of 2 (max), a specificgravity (25 C./ C.) of about 0.999, a density of about 8.3 lbs. pergallon, a viscosity (poises, C.) of about 3 to 4, a refractive index (Nof about 1.471, a freezing point of about +2 0., a flash point C.) ofabout 316, an acid number (mgs. KOH/gm.) of about 1 (max), and asaponification number (mgs. KOH/ gm.) of about 182.

The organosol component includes or is used in conjunction with astabilizer that inhibits thermal and ultraviolet decomposition. Liquidepoxy resins may be used wherein the viscosity is about 500 cps-20,000cps. and the epoxide equivalent is about 140-375. An epoxy resin may beused such as Bakelite ERL-2774. Bakelite ERL-2774 is a low molecularweight epoxy resin of the polyglycidyl polyether type which is formedfrom the reaction of bisphenol A with epichlorhydrin and is in the formof a viscous liquid and has a specific gravity of about 1.15-1.17, acolor (Gardner 1933 Standard) of 10 (max.), an epoxide equivalent ofabout 185-200, and is soluble (clear to light haze) in aromatics,ketones, and alcohols, but settles out in aliphatics.

Bakelite ERL-2774 also acts as an acid (e.g., hydrochloric acid)scavenger and thus heat-stabilizes the coating composition.

The vinyl chloride copolymer solution grade resin component contains apredominance of vinyl chloride and, for

purposes of the invention, may be a commercially available product suchas follows: Bakelite VMCH; Exon 470; Geon 400-X-110; Bakelite VYHH; andBakelite VAGH. Bakelite VMCH is preferred.

These modifiers may be more specifically identified as follows: BakeliteVMCH is a white, powdered solid containing a solvent polymerized vinylchloride-vinyl acetate copolymer (since the product contains apredominance of vinyl chloride and vinyl acetate, it may be consideredas being a copolymer despite its inclusion of some small amount ofmaleic acid) with a chemical composition of about 85.0 to 88.0% byweight of vinyl chloride, about 11.0 to 14.0% by weight vinyl acetate,about 0.8 to 1.2% by weight maleic acid, and having a specific viscosityfrom about 0.536 to 0.567 as measured by 1.0 gm. resin per m1. ofsolution in the methyl isobutyl ketone at 25 C.; Exon 470 is a vinylchloride monohydrogen monoalkyl ester of maleic acid copolymer such asvinyl chloridea one-half dibutyl maleate ester type copolymer (granularpowder), as disclosed in Rowland et a1. Patent 2,731,449, reissued asReissue Patent 24,206, and has a specific gravity of about 1.31, a bulkdensity (dry) of about 0.8 gm./cc., a bulk density (solution) of about0.091 gal./ 1b., and a relative viscosity (1% in cyclohexanone) of about1.35; Geon 400-X-1l0, a white powder, is a vinyl chloride-vinyl acetatecopolymer having about 9l%i2% vinyl chloride, about 6% i2% vinyl acetateand about 3% 12% maleic acid, and has been reported to have a specificviscosity (at 20 C.) of 0.24, a tensile strength of (2 mil film) 6,500,and 22-26% maximum working solvents; Bakelite VYHH contains about 87% byweight vinyl chloride and about 13% by weight vinyl acetate, and has anintrinsic viscosity of about 0.50-0.55 measured in cyclohexanone at 20C.; and Bakelite VAGH contains about 91% by weight vinyl chloride andabout 3% by weight vinyl acetate and about 6% by Weight vinyl alcohol inthe polymer which is produced by back-hydrolyzing some of the vinylacetate, and has an intrinsic viscosity of about 0.57 measured incyclohexanone at 20 C.

We prefer to use the vinyl chloride-vinyl acetate solntion resin insteadof the vinyl chloride-maleate solution resin.

The vinyl chloride-vinylidene chloride solution resin component may beomitted from the liquid coating composition, but we much prefer that itbe present because it adds moisture resistance or moistureimpermeability properties to the baked-on coating. This component mayconsist of products such as Geon 222. Geon 222 is a copolymer of vinylchloride and vinylidene chloride in proportions of about 26-445 byWeight vinylidene chloride, has a chlorine content of about 61-64% byweight, and has a specific viscosity of about 0.15-0.30 determined at 20C. in 0.4% solution of nitrobenzene.

In order to produce a superior product, the acrylic resin syrup shouldbe used irrespective of Whether the coating is to have either high glossor low gloss with low or high angular sheen. The acrylic syrup enhancesthe adhesion of the coating to metal and, most important, it contributessignificantly to the flexibility and exterior durability of the baked-oncoating. However, an inferior, but usable high or low gloss coatingcomposition having reduced flexibility may be prepared by replacing allor some of the acrylic syrup with an air-dry or bake-on acrylic resinsolution.

The syrup should be of the type disclosed in Belgian Patent 572,359,filed by E. I. du Pont de Nemours and Company, based on an applicationfiled in the United States on Nov. 5, 1957. For example, We have usedLucite 204-X Acrylic Syrup which is described in the Belgian pate'nt.Lucite 204-X has a viscosity of 15 :1 poises and a color, as measured asan APHA No., of not over about 15, a specific gravity as shipped of1.02, a specific gravity when completely polymerized of 1.18, and therefractive index of the cured or polymerized resin is 1.49. The activityof Lucite 204-X was measured on the Sunshine Gel Meter at 60 C. with 2%benzoyl peroxide dry powder as the catalyst, and was found to have about35 minutes gel time.

The acrylic syrup may contain at least about by weight of polymericmethyl methacrylate in methyl methacrylate monomer. The polymeric methylmethacrylate should have an intrinsic viscosity, at 0.5 gram perdeciliter, of about 0.25-1.0, measured in liquid chloroform. The syrupshould have a viscosity between about 0.5-50 poises at 'C. and containless than 20 p.p.m. of a polymerization initiator.

The syrup can be prepared by one of several suitable processes. Forexample, by partially polymerizing methyl methacrylate monomer by aprocess that produces the required polymer. Alternatively, a desiredamount of methyl methacrylate polymer of the required intrinsicviscosity may be dissolved in methyl methacrylate monomer.

In the former process, the syrup may be prepared by heating methylmethacrylate ester, free of polymerization inhibitor but containing asmall quantity of polymerization initiator, in the presence of a chaintransfer agent until the solution reaches a predetermined viscosity. Thepolymerization may be stopped by adding cold methyl methacrylate monomercontaining a polymerization inhibitor such as hydroquinone. For example,a syrup having a viscosity of between about 1-50 poises may be producedwith methyl methacrylate monomer, a small predetermined amount ofinitiator, and about 0.05l.0 mole percent of a chain transfer agent.This reaction mixture should be heated to a temperature of about 50150C. until the desired viscosity is reached and the initiator content isbelow 20 parts per million. Polymerization is then stopped by coolingthe reaction mixture, for example, by adding 1-10 parts by weight ofcold methyl methacrylate containing suificient hydroquinone to inhibitcompletely the polymerization.

An air-dry or bake solution type acrylic resin is used in combinationwith the acrylic syrup in producing our preferred high gloss coatingcompositions. The acrylic solution type resin is primarily used toproduce a coating with high gloss, although it also enhances, to somedegree, the exterior durability and adhesion properties of the bakedoncoating.

For example, the solution type acrylic resin includes resins such aspolymers and/or copolymers of methyl, ethyl, n-butyl and isobutylmethacrylate or acrylate. Acryloid B-44 and Acryloid A-21 may be used;and these particular products are polymers of esters of acrylic andmethacrylic acids which contain nitrogeneous heterocyclic ringsrendering the polymers susceptible to condensation reactions. AcryloidsB-44 and A-2l are described in U.S. Patent 2,881,155. Acryloid B-44contains about 40% resin, and a toluol solvent, and has a specificgravity of 0.97, a density of 8.1 lbs/gal, a viscosity of 600-1100centipoises at C., a color of TW (Gardner Holdt Scale), and a flashpoint of 39 F. (closed cup, Tag).

The pigment selected for use in the liquid coating composition should benon-reactive. Since basic pigments induce gelation, neutral pigmentsshould be used, such as titanium dioxide, cadmium yellow, phthalocyanineblue and green, cadmium red, quinacridone red, carbon black, syntheticpure iron oxides and flaked aluminum pigments.

When one wishes to produce a coating having a low gloss, fiatting agentssuch as fine-particle-size silica may be incorporated into the liquidcoating composition.

Silica products such as Santocel 54 and Syloid 162 may be used asflatting agents.

Santocel 54. is a light, fiuify, white silica aerogel having 94% deadair. It is composed of sub-ultramicroscopic fibers of silica having adiameter of about 25-35 angstroms spaced about 300 angstroms apart. Ithas an average particle size of 0.5-3.0 microns, an absolute den- 6 sityof 17.1 lbs/gal, an oil absorption value of 2.5 gm. oil/gin. (ASTM) andan index of refraction of 1.464.

Syloid 162 is a synthetic silica fiatting agent. This product is auniform free-flowing powder having an average radius of 4.5-6.5 microns,a dry bulk density (compacted) of 23 lbs./ft. a bulking value of 0.0606solid gal./ 1b., and an oil absorption value of 145.

The liquid coating composition should have about 20- 70% by weightnon-volatile material, preferably about 40-60% by weight non-volatilematerial, depending upon the pigment used and the method by which themetal is coated. When a white pigment such as TiO is used, the liquidcoating composition should preferably contain about 30-50% by weightpigment based on non-volatiles and the composition should preferablycontain about 40- 60% by weight non-volatile materials.

Table I illustrates various proportions that may be used to prepareeither a satisfactory fiat or high gloss liquid coating composition.

TABLE I Flat or high gloss liquid composition Percent by Weight based onweight of non-volatile Non-volatile constituents: materials 1 Acrylicresin component 2-40 Solution resins:

Vinyl chloride-vinyl acetate copolymer and/or vinyl chloride-one-halflower alkyl ester of maleic acid component 9-34 Vinylchloride-vinylidene chloride 00- polymer resin 0-11.5 Dispersionresin(s): Vinyl chloride resin 10-34 Stabilizer 0.5-11 Plasticizer 5-25Pigment 10-55 Percent by weight based on weight of volatile Volatileconstituents: materials Diluent 0-60 Solvent 40-100 1 The and the uponthe TABLE Ill-LIQUID FLAT OR HIGH GLOSS COMPOSITION rewenthlgyfllvlgight; Based on or o Non-Volatile Constituents g Materi l VolameHigh Gloss Low Gloss Acrylic Resin Com onent Solution Resins; p 5-25 215 Vinyl Chloride-Vinyl Acetate Copolymer and/or Vinyl Chloride-One-HalfLower Alkyl Ester of Maleic Acid Component 9-18 11-19 VinylChloride-Vinylidene Chloride Copolymer 1-6 1-6 Dispersion Res1n(s),Vinyl Chloride Resin 10-18 13-34 Stabilizer 0. 5-11 0 5-11 Plasticizer.9-18 5-18 Pigment 10-50 10-55 Percent by Weight Base;

on W eight of Volatile Materials M Volatile Constituents:

Diluent 30-60 30-60 Solvent 40-70 40-70 In order to produce a coatingcomposition having a fiat finish and high angular sheen, such asproduced by Example I, the solvent(s) and diluent(s) are first mixed andthe vinyl chloride copolymer solution resin dissolved therein. The vinylchloride-vinylidene chloride resin is then added and dissolved in thesolution. (Plasticizer(s), stabilizer(s), pigment(s), modifying resin(s)and flatting paste are then added. The fiatting paste comprises aflatting agent that has been previously dispersed in solvent and one ofthe modifying resins, and may be prepared by treating these constituentsin a pebble mill for about 6-8 hours.) The vinyl chloride dispersionresin is added last and the mixture stirred until a homogeneous mixtureis obtained. The mixture may then be processed through a high-speed sandmill (such as disclosed in U.S. Patent 2,581,414) to a Hegman finenessof about 6. The vinyl dispersion resin may be omitted from the grindportion of the formula and incorporated afterward under agitation.

If a low angular sheen, fiat finish is desired, such as produced byExample II, the flatting paste is omitted from the charge that istreated in the mill, and is later added to the material that is obtainedfrom the highspeed sand mill.

A high gloss coating composition, such as produced by Example III, maybe prepared by omitting the flatting agent and replacing it with theacrylic solution resin.

A high gloss coating composition is made by mixing the slvent(s) anddiluent(s), adding and dissolving the vinyl chloride copolymer solutionresin therein, and adding and dissolving therein the vinylchloride-vinylidene chloride resin. Plasticizer(s), stabilizer(s),acrylic syrup resin, air-dry or bake-type acrylic solution resin,pigment(s), and vinyl chloride dispersion resin may then be added andmixed therewith in a high-speed sand mill until a homogeneous mixtureand Hegman fineness of about 6.5-7 is obtained. This may require twopasses through the sand mill, instead of one as required for the flatmaterial.

EXAMPLE I Flat white coating composition with high angular sheenConstituents.Part A: Parts by weight Solution resin: Bakelite VMCH 84Plasticizer: Diisodecyl phthalate 26.5 Stabilizer: Bakelite ERL 2774 31Plasticizer-stabilizer: Paraplex G-62 Diluent: Penola 150 221 Solvent:

Isophorone 101 Diisobutyl ketone 116 Solvent-diluent: Butyl CarbitolSolution resin: Geon 222 10.5

Part B.(Pre-dispersed in a pebble mill for 68 hrs. to Hegman Fineness of6):

Flatting agent:

Syloid 162 11.3

Santocel 54 5.4 Solution resin: Bakelite VAGH 6.3 Solvent:

Methyl isobutyl ketone 40.2

Isophorone 34.8

Part C:

Organosol dispersion resin: Bakelite QYNV 75 Acrylic syrup:

Lucite 204X 72 Methyl methacrylate monomer 4.5 Pigment: 1 TiO 198 Total1072.5

1 Du Ponts R-610 rutile titanium dioxide.

EXAMPLE II Flat white coating composition with low angular sheenConstituents.--Part A: Parts by weight Solution resin: Bakelite VMCHPlasticizer: Diisodecyl phthalate 68 Stabilizer: Bakelite ERL 2774 22Plasticizer-stabilizer: Paraplex G-62 10 Diluent: Penola 150 162Solvent:

Isophorone 104 Diisobutyl ketone 113 Methyl isobutyl ketone 41Solvent-diluent: Butyl carbitol 27 Diluent-cosolvent: n-Butanol 10Solution resin: Geon 222 8 Part B.(Pre-dispersed in a pebble mill for 68hrs. to

Hegman Fineness of 6):

Flatting agent:

1 Du Pont's R610 rutile titanium dioxide.

EXAMPLE III High gloss white coating composition Constituents: Parts byweight Solution resin: Bakelite VMCH Plasticizer: Diisodecyl phthalate37 Plasticizer-stabilizer: Paraplex G-62 l9 Diluent: Penola 196 Solvent:

Isophorone 91 Diisobutyl ketone 103 Solvent-diluent: Butyl carbitol 19Solution resin: Geon 222 9 Organosol dispersion resin: Bakelite QYNV 66Acrylic syrup:

Lucite 204-X 67 Methyl methacrylate monomer 4 Acrylic solution resin(40% resin): Acryloid B-44 86 Stabilizer: Bakelite ERL 2774 28 Marresistance additive: 30% lanolin in penola 150 38 Flow control andanti-eyehold agent 15% 1 ethyl cellulose in butyl cellosolve 5 PigmentT10 245 Total 1088 1 Hercules Powder Co.s T-50. Du Ponts R-900 rutiletitanium dioxide.

Example IV, below, shows that the critical combination of resinouscomponents herein disclosed produced baked-on coatings that areunexpectedly superior to coatings produced with (a) the combination ofthe vinyl chloride dispersion resin component and vinyl chloridecopolymer solution resin component, or (b) the combination of thedispersion resin component and acrylic resin component, or (c) thecombination of the solution resin component and acrylic resin component.

As shown in detail in Example IV, four coating compositions wereprepared. Composition ABC included the combination of the vinyl chloridedispersion resin (A), solution grade vinyl chloride-vinyl acetatecopolymer resin (B), and acrylic resin (C), as herein disclosed.Composition AB contained the vinyl chloride dispersion resin andsolution grade vinyl chloride-vinyl acetate copolymer resin. CompositionAC included the vinyl chloride dispersion resin and acrylic resin.Composition BC included the solution grade vinyl chloridevinyl acetatecopolymer resin and acrylic resin.

In all of these liquid coating compositions, the dispersion resin,solution resin, and acrylic resin, when present, were used in weightratios of about 1.5 :1:0.35, respectively.

In one series of tests, compositions ABC, AB, AC and BC were eachapplied to test panels 0.019 in. thick made of steel and the coatedpanels were heated for minutes at 365 F. In a second series of tests,each of these compositions was applied to test panels 0.021 in. thickmade of aluminum, and the coated panels were heated for 10 minutes at365 F. In both series of tests, the test panels were baked in agas-fired, forced-air circulating oven. The test panels had about 10 mg.of bakedon coating per square inch of panel.

After the coatings were cured (in both series of tests), theirproperties were determined and reported.

Table III of Example IV concerns the coated steel panels, whereas TableIV of Example IV concerns coated aluminum panels. Each of these tablesshows the weather resistance, humidity resistance, salt sprayresistance, impact resistance, flexibility and adhesion, abrasionresistance, the relative cost, and appearance of each of compositionsABC, AB, AC and BC. Table V of Example IV describes procedures that wereused in determining properties of the baked-on coatings.

It is clear from Example IV that composition ABC produced asignificantly superior coating or film on both steel and aluminum thanwas obtained with each of the other compositions. In both series oftests, using both steel and aluminum substrates, composition ABC had amarkedly better combination of properties, as evidenced by Total Ratingvalues (determined by totaling the values obtained for all of the tests)shown in Tables III and IV, which combination of properties includesWeather resistance, humidity resistance, salt spray resistance, impactresistance, flexibility and adhesion, abrasion resistance andappearance. In addition, in conducting the tests, it was found thatComposition ABC cost less than the other compositions.

EXAMPLE IV A stabilized liquid coating composition having 30% by weightnon-volatile materials was prepared containing 475 parts by weight of avinyl chloride dispersion resin, 315 parts by weight of a solution gradevinyl chloridevinyl acetate copolymer, 110 parts by weight of an acrylicresin, and 16 parts by weight of a stabilizer, wherein the parts byweight are based on non-volatile constituents. The volatile constituentsconsisted of equal parts by weight of diisobutyl ketone and aromatichydrocarbon solvent.

This composition, hereinafter identified as composition ABC, had thefollowing composition:

COMPOSITION ABC Parts by weight non-volatile material Dispersion resin:Bakelite QYNV 475 Solution resin: Bakelite VMCH 315 Acrylic resin:Acryloid B-44 110 has a mixed aniline point F.) of 57; has a Kauri-Butanol value of 91; and has a Saybolt color of +30.

A second stabilized liquid coating composition having 30% by weightnon-volatile materials was prepared containing 540 parts by weight of avinyl chloride dispersion resin, 360 parts by weight of a solution gradevinyl chloride-vinyl acetate copolymer, and 18 parts by weight of astabilizer, wherein the parts by weight are based on nonvolatileconstituents. The volatile constituents consisted of equal parts byweight of diisobutyl ketone and aromatic hydrocarbon solvent (SolvessoThis composition, identified as composition AB, had the followingcomposition:

COMPOSITION AB Parts by weight non-volatile material Dispersion resin:Bakelite QYNV 540 Solution resin: Bakelite VMCH 360 Stabilizer: BakeliteERL-2774 18 COMPOSITION AC Parts by weight non-volatile materialDispersion resin: Bakelite QYNV 732 Acrylic resin: Acryloid B-44 168Stabilizer: Bakelite ERL-2774 14.5

A fourth stabilized liquid coating composition having 25% by weightnon-volatile materials was prepared containing 556 parts by weight of asolution grade vinyl chloride-vinyl acetate copolymer, 194 parts byweight of an acrylic resin, and 11 parts by weight of a stabilizer,wherein the parts by weight are based on non-volatile constituents. Thevolatile constituents consisted of equal parts by weight of diisobutylketone and aromatic hydrocarbon (Solvesso 100). This composition,identified as composition BC, had the following composition:

COMPOSITION BC Parts by weight non-volatile material Solution resin:Bakelite VMCH 556 Acrylic resin: Acryloid B-44 194 Stabilizer: BakeliteERL-2774 11 A stabilizer was included in the above liquid coatingcompositions to prevent charring of each of the coatings during the bakecycle.

All of the above liquid coating compositions contained 30% by weightnon-volatile materials except composition BC, which contained 25 byweight non-volatile materials in order to make it less viscous andfacilitate its application to test panels.

In all of the above liquid coating compositions, the aforesaiddispersion resin, solution resin, and acrylic resin, when present, wereused in weight ratios of about 1.5: l :0.35, respectively.

In one series of tests, compositions ABC, AB, AC and BC were eachapplied to test panels 0.019 in. thick made of treated steel and'thecoated panels were heated for 10 minutes at 365 F. The steel panels werepretreated in a conventional manner with Bonderite 1000 which isreported to form a phosphate coating in accordance with US. Patent2,609,308. In a second series of tests, each of these compositions wasapplied to test panels 0.021 in. thick made of treated aluminum, and

11 the coated panels were heated for minutes at 365 F. The aluminumpanels were pretreated in a conventional manner with Alodine 1200 whichis reported to form t c Q m l. c er om 553 0 MM M W m w m c m e c nnwbiufim o MM m c w m H o o m ow w i zmlw: omfi O w o o m o H o o N Ill-Manon a 3 5 8 5M 34 u g fiu :OmH wfi o 3.8 5? d :235 a eemfiwmw M Edam N5 35mm $333 39% wwen v $n$mn a Seamu a m an ezm am 395 2cm 2: c3 m 950we EE ES ga mnsm EV wQQEQ w u E o3 n c3 wmuo edvfiu flowing m can 0 $852$23 nw dwoh eeoom m n? emem a H HQMAJH 80 cs a m H m l w .I U :Om:QQEwQQEQO m M M m m m m m m 1 d i v nwbfiz E E O E m o w H o m o m 1 u lowl}ililiilIl-IH zm fi: floEmonEoO u o c m o o H c H 2. h on? 3 38m v nrs =OM E O a Seems mnawm Ga awv $258254 a c2354 a E NQ 853% a whim 2am NB B 15:23 59m 050 we E5 9352mm EC 386380 @5580 13 B 3 0 .S am 2: 3 mE o32: c3 wwno aswfim 232% m use c 5333 $33 weave uweeoemflm 25m; awomflgHHH manna.

. 5 5 m w m m w m w a m m m m m 7 1 a m m m a a m O r n b O O S c 2. m Tc n f 9 a l n a w 0 a d w Y .tu m n k b m e d 8 m p H e 1 u k C 6 m u eC a a a m mm m m o h W n b c H M o a m an amorphous chromate coating andto be composed of hexavalent chromium ions, fluoride ions andferricyanide ions similar to those described in US. Patent 2,796,370. Inboth series of tests, the test panels were baked in a gas-fired,forced-air circulating oven. The test panels had about 10 mg. ofbaked-on coating per square inch of panel.

After the coatings were cured (in both series of tests), theirproperties were determined and reported.

Table III, below, concerns the coated panels of treated steel, whereasTable IV, below, concerns the coated panels of treated aluminum. Each ofthese tables shows the weather resistance, humidity resistance, saltspray resistance, impact resistance, flexibility and adhesion, abrasionresistance, the relative cost, and appearance of each of compositionsABC, AB, AC and BC. Table V, below, describes procedures that were usedin determining properties of the baked-on coatings.

TABLE V.TESTS DESIGNATED IN TABLES III AND IV Subscript number in TablesIII and IV Test 1.Dew point weatherometer tests: This is considerablymore severe than a conventional Twin Arc Weatherometer. The coatedpanels are exposed to continuous cycles of one hour of ultra violetlight and one hour of darkness. All the while a cold water spray isimpinging on the backs of the panels.

Test 2.Test in humidity cabinet: Coatings are exposed to an atmosphereof relative humidity and at 100 F.

Test 3.Test in salt spray cabinet: Coatings are exposed to a salt fogcomposed of 5% sea salt in 95% water at 100 F.

Test 4.-Impact test with Gardner impact tester: Coated panels are bumpedby a 2-lb. weight falling through a measured distance, All aluminumpanels had 60 in./lbs. impact. (Higher impacts burst the metal). Allsteel panels had in./ lbs. impact.

Test 5.Flexibility and adhesion tests: These tests were made on a wedgebender which caused the metal to bend back on itself in a cone varyingfrom 0 inch radius to A inch radius. The bend had Scotch brand tapepressed firmly on the coating and pulled away. The amount of coatingpulled away is a measure of flexibility and adhesion.

Test 6.-Abrasion resistance test: Abrasion resistance was measured byuse of the Taber Abraser which counts the number of revolutions requiredfor two small abrasive wheels to grind through a measured film thic ing.CS-17 Abrader wheels were used with 1000 weights.

It is clear from the above series of tests that were used in evaluatingcoating compositions ABC, AB, AC, and BC that composition cantlysuperior coating or fil num, In both series of tests, using both steeland aluminum substrates, composition ABC ter combination of properties,as Rating values (determined by totaling the values obtained for all ofthe tests reported on a particular line) in Tables III and IV, whichcombination of properties includes weather resistance, humidityresistance, salt spray resistance, impact resistance, flexibility andadhesion, abrasion resistance, and appearance. In addition position ABCcost less than the other com The foregoing detailed description has beengiven for clearness of understanding only, and no unnecessarylimitations should be understood therefrom, as modifications will beobvious to those skilled in the art.

We claim:

1. A liquid coating composition suitable for use in coating metal andbeing baked thereon to provide an adherent coating, the resinous portionof said composition consisting essentially of: a vinyl chlorideorganosol dispersion resin containing at least about 90% by weight ofpolymerized vinyl chloride; a vinyl chloride copolymer solution resin,said copolymer being at least 80% by weight polymerized vinyl chlorideand being a member of the group consisting of vinyl chloride-vinylacetate and vinyl chloride monohydrogen monoalkyl ester of maleic acid;an acrylic resin component from the group consisting of acrylic resinsyrup containing at least 20% by weight of polymeric methyl methacrylatein methyl methacrylate monomer, acrylic solution resin, and admixturesthereof; and organic liquid vehicle; said composition having about20-70% by weight nonvolatiles containing about -34 parts by weightvinyl'chloride dispersion resin, about 9-34 parts by weight vinylchloride copolymer solution resin, and about 2-40 parts by weightacrylic resin component; and said composition being capable of beingapplied as a heat-stable, compatible, substantially homogeneouscomposition onto a metal surface and of being baked thereon at atemperature of about 350-450 F. to form a cured adherent coating.

2. The liquid coating composition of claim 1 in which said nonvolatilesinclude a vinyl chloride-vinylidene chloride solution resin that ispresent therein an amount not exceeding about 11.5 parts by weight.

3. The liquid coating composition of claim 1 in which the acrylic resinis an acrylic resin syrup of polymeric methyl methacrylate in methylmethacrylate monomer.

4. The liquid coating composition of claim 1 in which the acrylic resinis an acrylic solution resin.

5. The liquid coating composition of claim 1 which includes up to about11% by weight, based on the weight of the nonvolatiles, of a lowmolecular weight epoxide resin.

6. A heat-stable, liquid coating composition suitable for use in coatingmetal and being baked thereon to provide an adherent coating, theresinous portion of said composition consisting essentially of: a vinylchloride organosol dispersion resin containing at least about 90% byweight of polymerized vinyl chloride; a vinyl chloride copolymersolution resin, said copolymer being at least 80% by Weight polymerizedvinyl chloride and being a member of the group consisting of vinylchloride-vinyl acetate and vinyl chloride monohydrogen monoalkyl esterof maleic acid; an acrylic resin component from the group consisting ofacrylic resin syrup containing at least 20% by weight of polymericmethyl methacrylate in methyl methacrylate monomer, acrylic solutionresin, and admixture thereof; and organic liquid vehicle; saidcomposition having about 20-70% by weight nonvolatiles containing about10-34% by Weight vinyl chloride dispersion resin, about 9-34% by Weightvinyl chloride copolymer solution resin, and about 2-40% by weightacrylic resin; and said composition being capable of being applied as acompatible, substantially homogeneous composition onto a metal surfaceand of being baked thereon at a temperature of about 350-450 F. to forma cured adherent coating.

7. The liquid coating composition of claim 6 in which the acrylic resinis an acrylic resin syrup containing at least about 20% by weight ofpolymeric methyl methacrylate in methyl methacrylate monomer.

8. The liquid coating composition of claim 6 in which the acrylic resinis an acrylic solution resin.

9. A plasticized, stabilized, liquid coating composition suitable foruse in coating metal and being baked thereon to provide a stableadherent coating, the resinous portion of said composition consistingessentially of: a vinyl chloride organosol dispersion resin containingat least about 90% by wegiht of polymerized vinyl chloride; a vinylchloride copolymer solution resin, said copolymer being at least 80% byweight polymerized vinyl chloride and being a member of the groupconsisting of vinyl chloridevinyl acetate and vinyl chloridemonohydrogen monoalkyl ester of maleic acid; a vinyl chloride-vinylidenechloride solution resin; an acrylic resin component from the groupconsisting of acrylic resin syrup containing at least 20% by weight ofpolymeric methyl methacrylate in methyl methacrylate monomer, acrylicsolution resin, and admixture thereof; and organic liquid vehicle; saidcomposition having about 20-70% by weight nonvolatiles containing about10-34 parts by weight vinyl chloride dispersion resin, about 9-34 partsby weight vinyl chloride copolymer solution resin, not more than about11.5 parts by weight vinyl chloride-vinylidene chloride solution resin,and about 2-40 parts by weight acrylic resin; and said composition beingcapable of being applied as a compatible, substantially homogeneouscomposition onto a metal surface and of being baked thereon at atemperature of about 350- 45 0 F. to form a cured adherent coating.

10. A stabilized, liquid coating composition suitable for use in coatingmetal and being baked thereon to provide an adherent coating, theresinous portion of said composition consisting essentially of: a vinylchloride organosol dispersion resin containing at least about 90% byweight of polymerized vinyl chloride; a vinyl chloride copolymersolution resin, said copolymer being at least by weight polymerizedvinyl chloride and being a member of the group consisting of vinylchloride-vinyl acetate and vinyl chloride monohydrogen monoalkyl esterof maleic acid an acrylic resin component from the group consisting ofacrylic resin syrup containing at least 20% by Weight of polymericmethyl methacrylate in methyl methacrylate monomer, acrylic solutionresin, and admixture thereof; a non-reactive neutral pigment; andorganic liquid vehicle; said composition having about 20-70% by weightnonvolatiles containing about 10-34 parts by weight vinyl chloridedispersion resin, about 9-34 parts by weight vinyl chloride copolymerolution resin, about 2-40 parts by weight acrylic resin, and about 10-55parts by weight pigment; and said composition being capable of beingapplied as a compatible, substantially homogeneous composition onto ametal surface and of being baked thereon at a temperature of about350-450 F. to form a stable, flexible, cured adherent coating.

11. A liquid coating composition suitable for use in coating metal andbeing baked thereon to provide an adherent coating, the resinous portionof said composition consisting essentially of: a vinyl chlorideorganosol dispersion resin containing at least about by weight ofpolymerized vinyl chloride; a vinyl chloride copolymer solution resin,said copolymer being at least 80% by weight polymerized vinyl chlorideand being a member of the group consisting of vinyl chloride-vinylacetate and vinyl chloride monohydrogen monoalkyl ester of maleic acid;a non-air-drying acrylic casting resin syrup component containing atleast 20% by weight of polymeric methyl methacrylate in methylmethacrylate monomer; and organic liquid vehicle; said compositionhaving about 20-70% by weight nonvolatiles containing about 10-34 partsby weight vinyl chloride dispersion resin, about 9-34 parts by weightvinyl chloride copolymer solution resin, and about 2-40 parts by weightacrylic resin component; and said composition being capable of beingapplied as a heat-stable, compatible, substantially homogeneouscomposition onto a metal surface and of being baked thereon at atemperature of about BSD-450 F. to form a cured adherent coating.

12. The liquid coating composition of claim 11 which includes up toabout 11% by weight, based on the Weight of the nonvolatiles, of a lowmolecular weight epoxide resin.

13. A metal article whose surface is provided with a baked-on adherentcoating, said coating being produced by baking on the article astabilized, liquid, substantially homogeneous compatible coatingcomposition the resinous portion of which consists essentially of: avinyl chloride organosol dispersion resin containing at least about 90%15 by weight of polymerized vinyl chloride; a vinyl chloride copolymersolution resin, said copolymer being at least 80% by Weight polymerizedvinyl chloride and being a member of the group consisting of vinylchloride-vinyl acetate and vinyl chloride monohydrogen monoalkyl esterof maleic acid, an acrylic resin component from the group consisting ofacrylic resin syrup containing at least 20% by weight of polymericmethyl methacrylate in methyl methacrylate monomer, acrylic solutionresin, and admixtures thereof, and organic liquid vehicle; said liquidcomposition having about 20-70% by weight nonvolatiles containing about10-34 parts by Weight vinyl chloride dispersion resin, about 9-34 partsby weight vinyl chloride copolymer solution resin, and about 240 partsby weight acrylic resin component; and said liquid composition beingcapable of being applied as a compatible, substantially homogeneouscomposition onto the metal surface of the article and of being bakedthereon at a temperature of about 350-450 F. to form a cured adherentcoating.

References Cited UNITED STATES PATENTS 3,154,600 10/1964 Munn 260-8843,305,602 2/1967 Bromstead 260884 ALLAN LIEBERMAN, Primary Examiner.

US. Cl. X.R.

